Search Results

Search found 58566 results on 2343 pages for 'data modelling'.

Page 43/2343 | < Previous Page | 39 40 41 42 43 44 45 46 47 48 49 50  | Next Page >

  • Calculations in a table of data

    - by Christian W
    I have a table of data with survey results, and I want to do certain calculations on this data. The datastructure is somewhat like this: ____________________________________________________________________________________ | group |individual | key | key | key | | | |subkey|subkey|subkey|subkey|subkey|subkey|subkey|subkey|subkey| | | |q|q|q |q |q |q|q|q |q|q|q |q |q |q|q|q |q|q|q |q |q |q|q|q | |-------|-----------|-|-|--|--|---|-|-|--|-|-|--|--|---|-|-|--|-|-|--|--|---|-|-|--| | 1 | 0001 |1|7|5 |1 |3 |1|4|1 |1|7|5 |1 |3 |1|4|1 |1|7|5 |1 |3 |1|4|1 | | 1 | 0002 |1|7|5 |1 |3 |1|4|1 |1|7|5 |1 |3 |1|4|1 |1|7|5 |1 |3 |1|4|1 | | 1 | 0003 |1|7|5 |1 |3 |1|4|1 |1|7|5 |1 |3 |1|4|1 |1|7|5 |1 |3 |1|4|1 | | 2 | 0004 |1|7|5 |1 |3 |1|4|1 |1|7|5 |1 |3 |1|4|1 |1|7|5 |1 |3 |1|4|1 | | 2 | 0005 |1|7|5 |1 |3 |1|4|1 |1|7|5 |1 |3 |1|4|1 |1|7|5 |1 |3 |1|4|1 | | 3 | 0006 |1|7|5 |1 |3 |1|4|1 |1|7|5 |1 |3 |1|4|1 |1|7|5 |1 |3 |1|4|1 | | 4 | 0007 |1|7|5 |1 |3 |1|4|1 |1|7|5 |1 |3 |1|4|1 |1|7|5 |1 |3 |1|4|1 | ------------------------------------------------------------------------------------ Excuse my poor ascii skills... So, every individual belongs to a group, and has answered some questions. These questions are always grouped in keys and subkeys. Is there any simple method to calculate averages, deviations and similar based on the groupings. Something like public float getAverage(int key, int individual); float avg = getAverage(5,7); I think what I'm asking is what would be the best way to structure the data in C# to make it as easy as possible to work with? I have started making classes for every entity, but I got confused somewhere and something stopped working. So before I continue along this path, I was wondering if there are any other, better, ways of doing this? (Every individual can also have describing variables, like agegroup and such, but that's not important for the base functionality.) Our current solution does all calculations inline in the queries when requesting the data from the database. This works, but it's slow and the number of queries equals questions * individuals + keys * individuals, which could be alot if individual queries. Any suggestions?

    Read the article

  • Modelling boost::Lockable with semaphore rather than mutex (previously titled: Unlocking a mutex fr

    - by dan
    I'm using the C++ boost::thread library, which in my case means I'm using pthreads. Officially, a mutex must be unlocked from the same thread which locks it, and I want the effect of being able to lock in one thread and then unlock in another. There are many ways to accomplish this. One possibility would be to write a new mutex class which allows this behavior. For example: class inter_thread_mutex{ bool locked; boost::mutex mx; boost::condition_variable cv; public: void lock(){ boost::unique_lock<boost::mutex> lck(mx); while(locked) cv.wait(lck); locked=true; } void unlock(){ { boost::lock_guard<boost::mutex> lck(mx); if(!locked) error(); locked=false; } cv.notify_one(); } // bool try_lock(); void error(); etc. } I should point out that the above code doesn't guarantee FIFO access, since if one thread calls lock() while another calls unlock(), this first thread may acquire the lock ahead of other threads which are waiting. (Come to think of it, the boost::thread documentation doesn't appear to make any explicit scheduling guarantees for either mutexes or condition variables). But let's just ignore that (and any other bugs) for now. My question is, if I decide to go this route, would I be able to use such a mutex as a model for the boost Lockable concept. For example, would anything go wrong if I use a boost::unique_lock< inter_thread_mutex for RAII-style access, and then pass this lock to boost::condition_variable_any.wait(), etc. On one hand I don't see why not. On the other hand, "I don't see why not" is usually a very bad way of determining whether something will work. The reason I ask is that if it turns out that I have to write wrapper classes for RAII locks and condition variables and whatever else, then I'd rather just find some other way to achieve the same effect. EDIT: The kind of behavior I want is basically as follows. I have an object, and it needs to be locked whenever it is modified. I want to lock the object from one thread, and do some work on it. Then I want to keep the object locked while I tell another worker thread to complete the work. So the first thread can go on and do something else while the worker thread finishes up. When the worker thread gets done, it unlocks the mutex. And I want the transition to be seemless so nobody else can get the mutex lock in between when thread 1 starts the work and thread 2 completes it. Something like inter_thread_mutex seems like it would work, and it would also allow the program to interact with it as if it were an ordinary mutex. So it seems like a clean solution. If there's a better solution, I'd be happy to hear that also. EDIT AGAIN: The reason I need locks to begin with is that there are multiple master threads, and the locks are there to prevent them from accessing shared objects concurrently in invalid ways. So the code already uses loop-level lock-free sequencing of operations at the master thread level. Also, in the original implementation, there were no worker threads, and the mutexes were ordinary kosher mutexes. The inter_thread_thingy came up as an optimization, primarily to improve response time. In many cases, it was sufficient to guarantee that the "first part" of operation A, occurs before the "first part" of operation B. As a dumb example, say I punch object 1 and give it a black eye. Then I tell object 1 to change it's internal structure to reflect all the tissue damage. I don't want to wait around for the tissue damage before I move on to punch object 2. However, I do want the tissue damage to occur as part of the same operation; for example, in the interim, I don't want any other thread to reconfigure the object in such a way that would make tissue damage an invalid operation. (yes, this example is imperfect in many ways, and no I'm not working on a game) So we made the change to a model where ownership of an object can be passed to a worker thread to complete an operation, and it actually works quite nicely; each master thread is able to get a lot more operations done because it doesn't need to wait for them all to complete. And, since the event sequencing at the master thread level is still loop-based, it is easy to write high-level master-thread operations, as they can be based on the assumption that an operation is complete when the corresponding function call returns. Finally, I thought it would be nice to use inter_thread mutex/semaphore thingies using RAII with boost locks to encapsulate the necessary synchronization that is required to make the whole thing work.

    Read the article

  • C# : Filtering data of data table using select method

    - by Royson
    I have data table containing one column as FilePath. FilePath D:\New folder\link.txt D:\New folder\SharepointMigration(Work Schedule).xls D:\New folder\my2\link.txt D:\New folder\my2\SharepointMigration(Work Schedule).xls D:\New folder\my2\my3\New Text Document.txt D:\New folder\Try.txt I am filtering my data table by DataRow[] dtRow = dataTable_FilesWithMetaData.Select("FilePath Like '" + sourcePath + "%'"); But it gives me all files and subfolder files. But i want only files not subfolders. How to write such type of filter expression..??

    Read the article

  • Modelling class relations

    - by phenevo
    Hi, I have a few classes: Article ------- Content ID Magazine -------- Name Code And 3 tables in database: Articles Magazines ArticlesInMagazines (two fields: IDArticle and CodeMagazine) In my app, I've got a module to manage Articles, and a datagridview to relate their associated magazines DataGridView has twofields: MagazineCode IsPublished (indicates articles which have been published in this magazine). The same article can be in many magazines (1:n) How would you implement on model ? Article have to has a field : List ?? I am concerned because Magazine associates Articles

    Read the article

  • Data Mining project ideas?

    - by Andriyev
    Hi I am looking for project ideas in the field of data mining. I expect to complete it in a quarter and intend to use C++, Linux as the environment. The course I'm taking aims to build the basics of data mining and covers topics like Classification, Regression-Modeling, Clustering and Association learning. Please point me to some good ideas which I can chew on. cheers

    Read the article

  • SQL Server, varchar data to nvarchar data

    - by Øyvind
    I've got a database with collation Danish_Norwegian_CS_AS and lots of varchar columns. I'd like to convert all this data to unicode, but haven't found a way to convert this data yet. If I've understood correctly, the encoding used is UCS-2 little endian. For example I've got a column containing 'PÃ¥l-Trygve' which is easily converted with C# to 'Pål-Trygve' using Encoding.Default.GetString(Encoding.UTF8.GetBytes("PÃ¥l-Trygve")); Is there a way to do this conversion in the Microsoft SQL Server client?

    Read the article

  • [Python] - Getting data from external program

    - by Kenny M.
    Hey, I need a method to get the data from an external editor. def _get_content(): from subprocess import call file = open(file, "w").write(some_name) call(editor + " " + file, shell=True) file.close() file = open(file) x = file.readlines() [snip] I personally think this is a very ugly way. You see I need to interact with an external editor and get the data. Do you know any better approaches/have better ideas?

    Read the article

  • Great data mining quotes

    - by Andrei Savu
    I'm searching some data mining related quotes. Can you tell me some of the quotes you like? On the internet I have only found this site: http://www.quotesea.com/quotes/with/data%20mining Thanks.

    Read the article

  • Modelling a manyToMany relationship with attributes

    - by Javi
    Hello, I have a ManyToMany relationship between two classes, for instance class Customer and class Item. A customer can buy several items and an item can be bought by different customers. I need to store extra information in this relationship, for example the day when the item was bought. I wonder how is this usually modelled in JPA, cause I'm not sure how to express this in code. Do I have to create a new class to model all the attributes of the relationship and make a manyToMany relationship between the other classes or is a better way to do this? Thanks

    Read the article

  • svg data visualizations

    - by garymlewis
    I'd like to experiment with SVG as a way of displaying data-driven graphs, charts, etc. The data exists as xml, and I'll use XQuery to produce the xml. What options (eg, graphics libraries) should I consider for creating the SVG from the xml? Many thanks.

    Read the article

  • UML Modelling in C++Builder 2010 Professional

    - by Gordon Brandly
    I'd like to do some basic class diagram UML models in the Pro version of C++Builder 2010. Embarcadero has a C++Builder Features Matrix document, one line of which says "UML Code Visualization – at any time, get a UML model view of your source code" and has a check in the "Professional" column of that table -- I assume this means it should be available to me. Yet, when I open an existing project and do a View | Model View, there's nothing in the Model View window. The only diagram I can find is on the Graph tab of the C++ Class Explorer. I wouldn't call that a UML diagram myself -- is that what Embarcadero is referring to? Embarcadero's table shows that many UML diagrams are not available in Pro, but it looks to me like Class Diagrams should be available. Other lines in that same table indicate that both "Full two-way class diagrams with synchronization between code and diagrams" and "Diagram hyper-linking and annotations" are also supposed to be available in Pro. The Class Explorer graph is one-way only as far as I can tell, so I hope they're referring to something else I haven't been able to find so far. Thanks for any insight into this.

    Read the article

  • Best Practices for Exchanging data between Desktop and Web Application

    - by Amitd
    Hi, I have to pass information from a desktop application to Web application and vice versa. What are the best practices that are regularly used? Currrently I'm using Asp.Net and a Winform. To pass data to Web Site im creating a (POST) WebRequest and posting an xml to the site. To pass data to Application im using .Net Remoting from Asp.net (Winform is an adminstration and monitoring application) Also currently both Web app and Winform are on the same machine.(but can change).

    Read the article

  • Data-Virtualization problem with SurfaceScrollViewer

    - by TWith2Sugars
    I'm in a situation where I'm using an ItemsControl with a SurfaceScrollViewer bound to an AsyncVirtualizingCollection and all of the data is being requested. I'm aware that it's due to the ItemsControl request all of the data but I'm not sure how to get around this. I've tried the AsyncVirtualizingCollection bound to a ListBox and it works fine and I'm now attempting to having it bound to a SurfaceListBox but the problem persists. Any ideas of how to overcome this? Thanks & Regards Tony

    Read the article

  • MSSQL, varchar data to nvarchar data

    - by Øyvind
    I've got a database with collation Danish_Norwegian_CS_AS and lots of varchar columns. I'd like to convert all this data to unicode, but haven't found a way to convert this data yet. If I've understood correctly, the encoding used is UCS-2 little endian. For example I've got a column containing 'PÃ¥l-Trygve' which is easily converted with C# to 'Pål-Trygve' using Encoding.Default.GetString(Encoding.UTF8.GetBytes("PÃ¥l-Trygve")); Is there a way to do this conversion in the microsoft SQL client?

    Read the article

  • C# SQL Data Adapter System.Data.StrongTypingException

    - by René
    I get my data from SQL to Dataset with Fill. It's just one table with two columns (CategoryId (int) and CategoryName (varchar)). When I look at my dataset after fill method, CategoryId Columns seems to be correct. But in the CategoryName I have a *System.Data.StrongTypingExceptio*n. What could that mean? Any Ideas?

    Read the article

  • which iphone data model to choose?

    - by Tronic
    i need to get some data somewhere to put in a timeline. the data strcture is like this: - Item - Name - Year - ShortInfo (mainly keywords and short texts) - LongInfo (much text with videos/audios (urls) a friend of mine told me i should you a plist and get all that stuff in there, but what about a sqlite database? any advice? regards

    Read the article

  • Reading numeric Date value from CSV file to data.frame in "R"

    - by Dick Eshelman
    D <- read.csv("sample1.csv", header = FALSE, sep = ",") D V1 V2 V3 V4 1 20100316 109825 352120 239065 2 20100317 108625 352020 239000 3 20100318 109125 352324 241065 D[,1] [1] 20100316 20100317 20100318 In the above example how do I get the data in D[,1] to be read, and stored as date values: 2010-03-16, 2010-03-17, 2010-03-18 ? I have lots of data files in this format. TIA,

    Read the article

  • WPF DataGrid bind data between columns

    - by Markus2k
    Lets say I have 2 columns in my data Grid: Column A: Selected, and Column B: Name. The Selected column is a checkbox. And Name column is text field. I want to set the color of the text in 'Name' column as Blue if Column A's check box is checked, and Red otherwise. Essentially I don't know how to bind data between columns of the datagrid. And sample code/link providing example would be useful.

    Read the article

  • Database Modelling - Conceptually different entities but with near identical fields

    - by Andrew Shepherd
    Suppose you have two sets of conceptual entities: MarketPriceDataSet which has multiple ForwardPriceEntries PoolPriceForecastDataSet which has multiple PoolPriceForecastEntry Both different child objects have near identical fields: ForwardPriceEntry has MarketPriceDataSetId (foreign key to parent table) StartDate EndDate SimulationItemId ForwardPrice PoolPriceForecastEntry has PoolPriceForecastDataSetId (foreign key to parent table) StartDate EndDate SimulationItemId ForecastPoolPrice If I modelled them as separate tables, the only difference would be the foreign key, and the name of the price field. There has been a debate as to whether the two near identical tables should be merged into one. Options I've thought of to model this is: Just keep them as two independent, separate tables Have both sets in the one table with an additional "type" field, and a parent_id equalling a foreign key to either parent table. This would sacrifice referential integrity checks. Have both sets in the one table with an additional "type" field, and create a complicated sequence of joining tables to maintain referential integrity. What do you think I should do, and why?

    Read the article

  • Core Data deleteObject: sets attributes to nil

    - by SG1
    I am implementing an undo/redo mechanism in my app. This works fine for lots of cases. However, I can't undo past deleteObject:. the object is correctly saved in the undo queue, and I get it back and reinsterted into the Core Data stack just fine when calling undo. The problem is that all it's attributes are getting set to nil when I delete it. I have an entity "Canvas" with a to-many relationship called "graphics" to a "Graphic" entity, which has its inverse set to "canvas". Deleting a Graphic, then inserting it back, doesn't work. Here's the code (the redo method is basically the same): - (void)deleteGraphic:(id)aGraphic { //NSLog(@"undo drawing"); //Prepare the undo/redo [self.undoManager beginUndoGrouping]; [self.undoManager setActionName:@"Delete Graphic"]; [[self.detailItem valueForKey:@"graphics"] removeObject:aGraphic]; [[self managedObjectContext] deleteObject:aGraphic]; //End undo/redo [self.undoManager registerUndoWithTarget:self selector:@selector(insertGraphic:) object:aGraphic]; [self.undoManager endUndoGrouping]; NSLog(@"graphics are %@", [self sortedGraphics]); //Update drawing [self.quartzView setNeedsDisplay]; } and here's the wierdness: Before delete: graphics are ( <NSManagedObject: 0x1cc3f0> (entity: Graphic; id: 0x1c05f0 <x-coredata:///Graphic/t840FE8AD-F2E7-4214-822F-7994FF93D4754> ; data: { canvas = 0x162b70 <x-coredata://A919979E-75AD-474D-9561-E0E8F3388718/Canvas/p20>; content = <62706c69 73743030 d4010203 04050609 0a582476 65727369 6f6e5424 746f7059 24617263 68697665 7258246f 626a6563 7473>; frameRect = nil; label = nil; order = 1; path = "(...not nil..)"; traits = "(...not nil..)"; type = Path; }) After redo: graphics are ( <NSManagedObject: 0x1cc3f0> (entity: Graphic; id: 0x1c05f0 <x-coredata:///Graphic/t840FE8AD-F2E7-4214-822F-7994FF93D4754> ; data: { canvas = nil; content = nil; frameRect = nil; label = nil; order = 0; path = nil; traits = nil; type = nil; }), You can see it's the same object, just totally bleached by Core Data. The relationship delete rouls apparently have nothing to do with it as I've set them to "No Action" in a test.

    Read the article

< Previous Page | 39 40 41 42 43 44 45 46 47 48 49 50  | Next Page >